I'm amazed at people who get by just using their browser to surf the web without any 3rd party tools for saving and sharing bookmarks. For anybody that visits a lot of web sites, and wants to share them with friends and co-workers, I find three web sites to be invaluable (full disclosure - I worked on 2 of the 3 products - but I genuinely love what they do for me).
Faves.com - Faves is a Social Bookmarking web site. Which means, it allows me to save Bookmarks I find interesting in my own on-line database. I primarily use Faves for two reasons: a) I can save web sites for myself for easy recall in the future, and b) sharing interesting things I find with my friends and family (and by sharing - I mean this is a two-way street; I find cool stuff for them, and they expose me to cool stuff they find). Faves has a really good built-in search engine so I can quickly find any Fave I've saved in the past (over 6,000 of them so far!) - or even search across the bookmarks all my friends have saved.
Faves is one of the first places I go to look for a recommendations for a resource on the web, or even product recommendations from my friends. Faves also sports a Facebook application, so my friends on Facebook get notified when I share something, as well as friends who are also using Faves directly.
Go2.me - Go2.me is a link shortening service with a twist; it not only can convert any long URL into a very short one (just 16 characters long), it creates a landing page where you and your friends can exchange comments. If you share links with friends over Twitter or email, you don't really know how many people are actually visiting your link, or have a good way to have a conversation about that link. Go2.me adds a wrapper around your shared page that shows you the number of visitors, and allows them to leave comments for you.
Foxmarks - Unlike the socially oriented tools, above, Foxmarks is a great utility for roaming your very frequently used bookmarks. Since I frequently use 4 different computers, Foxmarks can synchronize my Bookmarks toolbar across all of my machines. I have about 30 sites that I go back to over and over again in the course of my day - this way I can organize my Bookmark toolbar in one way, and Foxmarks will propogate my changes to each of my machines. You can also access your bookmarks directly from the web, if you are traveling and using a computer at a hotel, library, or Internet cafe.
I'm a pretty new convert to Foxmarks; the setup was really simple, and it even did a decent job of merging the disparate collection of bookmarks I had on three separate machines.
All of these tools are free - hopefully they'll make your Internet usage a richer and more productive experience. Feel free to add recommendations for other Bookmark-related tools in the comments.